System, apparatus, and method for facilitating interface with laryngeal structures

ABSTRACT

A system and method of introducing interface elements for interfacing with laryngeal structures of a subject such as for diagnosis or treatment of a laryngeal impairment is presented. Illustrative embodiments include generating a tunnel in geographical relation to the lateral wing of the cricoid cartilage of the subject and introducing at least one interface element via the tunnel for interfacing with at least one laryngeal structure of the subject.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from the following U.S. ProvisionalPatent Applications, all of which are hereby incorporated herein byreference in their entireties:

U.S. Provisional Patent Application No. 60/824,064 entitled ElectrodeInsertion System and Method for Vocal Chord Stimulation filed Aug. 30,2006 in the names of Müller and Förster;

U.S. Provisional Patent Application No. 60/824,065 entitled ElectrodeInsertion System and Method for Vocal Chord Stimulation filed Aug. 30,2006 in the names of Müller and Lindenthaler;

U.S. Provisional Patent Application No. 60/824,066 entitled ElectrodeInsertion System and Method for Vocal Chord Stimulation filed Aug. 30,2006 in the name of Müller and Förster;

U.S. Provisional Patent Application No. 60/824,072 entitled ElectrodeInsertion System and Method for Vocal Chord Stimulation filed Aug. 31,2006 in the name of Lindenthaler; and

U.S. Provisional Patent Application No. 60/824,067 entitled ElectrodeInsertion System and Method for Vocal Chord Stimulation filed Aug. 30,2006 in the name of Hagen.

This application is also related to the following U.S. PatentApplications, all of which are being filed on even date herewith and arehereby incorporated herein by reference in their entireties:

U.S. patent application entitled System, Apparatus, and Method forFacilitating Interface with Laryngeal Structures filed in the names ofLindenthaler and Förster;

U.S. patent application entitled System, Apparatus, and Method forFacilitating Interface with Laryngeal Structures filed in the names ofMüller and Förster;

U.S. patent application entitled System, Apparatus, and Method forFacilitating Interface with Laryngeal Structures filed in the name ofLindenthaler); and

U.S. patent application entitled System, Apparatus, and Method forFacilitating Interface with Laryngeal Structures filed in the names ofMüller, Förster, and Hagen.

FIELD OF THE INVENTION

The invention generally relates to an insertion system for laryngealstructures and, more particularly, the invention relates to an interfaceelement (such as an electrode) insertion system and method forfacilitating an interface with laryngeal structures (such as vocal cordstimulation).

BACKGROUND OF THE INVENTION

Functional electrical stimulation (“FES”) is the application ofstimulation devices to nerves and muscles to treat medical disorders.The most successful FES system to date is the cardiac pacer which hasbecome a routine part of cardiac disease therapy: Lynch, CardiovascularImplants, in Implants, Lynch ed., Van Nostrand Rheinhold, New York 1982,incorporated herein by reference. However, there are a variety of otherFES systems. The most heavily researched are FES systems to restorelocomotion to paraplegics and arm motion to quadriplegics: Peckham, IEEETrans. Biomed. Eng. 1991, 28: 530, incorporated herein by reference.Other motor control devices restore bladder control to paraplegics anddiaphragm function to high quadriplegics: Erlandson, Scand. J. Urol.Nephrol. 44 Suppl: 31, 1978; Glenn, Ann. Surg. 183: 566, 1976,incorporated herein by reference. There are also FES devices designed torehabilitate the sensory deficits, such as the cochlear implant:Hambrecht, Ann. Otol. Rhinol. Laryngol. 88: 729, 1979, incorporatedherein by reference.

The recurrent laryngeal nerve, which innervates the larynx, containsmotor fibers that innervate both the abductor/opener and adductor/closermuscles of the vocal folds. Damage to this nerve compromises both ofthese functions and arrests the vocal fold just lateral to the midline.In unilateral paralysis, the voice is breathy and aspiration can occurbecause of compromised adduction, but airflow during inspiration isminimally impaired. Adequate ventilation of the lungs is assured becauseabduction of the opposite fold can still occur with each inspiration. Inbilateral paralysis, there is a loss of abductory function in bothfolds, the voice may be minimally impaired because of fold symmetry andtheir paramedian position in most of the patients, but airwaydiscomfiture is usually severe. Typically, the patient can toleraterestricted activity or may be relegated to a sedentary lifestyle untiltreatment is administered. In some situations, however, the conditionmay be life-threatening.

Clinical management of vocal fold paralysis focuses on the majorlaryngeal dysfunction associated with each of these two main types.Conventional treatments for unilateral paralysis aim at medializing thefold to improve voice production. Treatment for bilateral paralysistypically requires a tracheotomy to restore sufficient airflow to thelungs. The tracheotomy is left in place until nerve regeneration andmuscle reinnervation has returned. However, in many cases, musclereinnervation is either incomplete or inappropriate resulting in chronicparalysis. Under such conditions, surgical resection of the vocal fold(i.e., cordotomy) is employed to permanently increase the airway andrelieve the patient of his tracheotomy. Although these conventionalmethods of treatment have been useful, they are less than ideal, sincethey tend to improve upon one laryngeal function at the expense ofanother. For example, cordotomy improves ventilation, but compromisesvoice production and airway protection.

Surgical techniques, such as laser arytenoidectomy and partialcordectomy, can be performed to widen the airway and relieve dyspnea inthe case of chronic paralysis. However, these procedures compromisevoice and airway protection to restore ventilation through the mouth.They also ignore the long-term effects of ensuing atrophy on vocal foldmass and position. In general, the greater the cartilaginous ormembranous resection associated with either technique, the greater themorbidity. A number of modifications of these two strategies have beendevised in an attempt to strike a more delicate balance between improvedoral ventilation and impaired voice and swallowing. However, a moreconservative stance toward resection increases the probability of failedintervention and the necessity for revision surgery. A new, morephysiological approach termed laryngeal pacing has been studied inanimal models as a means to restore oral ventilation.

Application of FES to paralyzed laryngeal muscles was introduced intohuman clinical otolaryngology in 1977 by Zealear D L, Dedo H H, ControlOf Paralyzed Axial Muscles By Electrical Stimulation, Acta Otolaryngol(Stockholm) 1977, 83:514-27, incorporated herein by reference, whichspecifically addressed the case of unilateral vocal fold paralysis.Patients normally breathe well, but they cannot approximate both vocalfolds. As a result, their voice is weak and breathy, and they tend toaspirate fluids. Zealear and Dedo proposed that a unilaterally paralyzedpatient could be reanimated to close appropriately by electricalstimulation triggered by signals relayed from its contralateral partner.As simpler surgical methods were discovered to restore function inunilateral vocal fold paralysis, the development of an implantableneuroprostheses for this condition has not been vigorously pursued.

Mayr, Zrunek, et al., A Laryngeal Pacemaker For Inspiration ControlledDirect Electrical Stimulation Of Denervated Posterior CricoarytaenoidMuscle In Sheep, Eur. Arch. Otorhinolaryngol, 248(8):445-448, 1991,incorporated herein by reference, described 8 sheep with denervated PCAswhich received implants for from 5-18 months, and ruled outreinnervation by control.

Obert et al., Use Of Direct Posterior Cricoarytenoid Stimulation InLaryngeal Paralysis, Arch. Otolaryngol 1984, 110: 88-92, incorporatedherein by reference, restored full abduction in bilaterally denervateddogs implanted with single-stranded teflon electrodes, using 20 msstimulus pulses delivered at 20-40 Hz and 2-3 mA. Their study suggestedthat stimulus pulses should be synchronized with inspiratory signals inabductor pacing. Bergmann et al., Respiratory Rhythmically RegulatedElectrical Stimulation Of Paralyzed Muscles, Laryngoscope, 1984,94:1376-80, incorporated herein by reference, successfully implantedthis idea of respiratory regulation of stimuli, using signals relayedfrom chest wall expansion. Canine PCA muscles were activated usingparameters of 30 Hz, 1 ms, and large amplitudes of up to 50 mA.

Kano and Sasaki, Pacing Parameters of the Canine PosteriorCricoarytenoid Muscle, Ann. Otol. Rhinol. Laryngol., 100:584-588, 1991,incorporated herein by reference, used a pair of coiled electrodes,separated by 2 mm, to stimulate the PCA. They observed promisingabductions at 60-90 Hz and 2 ms. Bergmann et al reported 2-3 mm ofabduction with stimulation of the PCA using a stimulus delivery systemthat had been chronically implanted for 11 months.

Otto et al, Coordinated Electrical Pacing Of Vocal Cord Abductors InRecurrent Laryngeal Nerve Paralysis, Otolaryngol. Head Neck Surg., 1985,93:634-8, incorporated herein by reference, used electromyographic (EMG)signals from the diaphragm to regulate stimuli to denervated canine PCAmuscles, and reportedly restored full abduction of the glottis.

Zealear and Herzon, Technical Approach For Reanimation Of TheChronically Denervated Larynx By Means Of Functional ElectricalStimulation, Ann. Otol. Rhinol. Laryngol., September 1994,103(9):705-12, incorporated herein by reference, first introduced use oftiny coiled electrodes for abductor pacing in a study of inspiratorytrigger sources including tracheal elongation, diaphragm EMG signals,phrenic nerve activity, and intrathoracic pressure changes.

Zealear et al, Technical Approach For Reanimation Of The ChronicallyDenervated Larynx By Means Of Functional Electrical Stimulation, Ann.Otol. Rhinol. Laryngol. 1994, 103: 705-12, incorporated herein byreference, implanted an electrode array 3 months after RLN section, andthe paralyzed stump was electro stimulated to rule out reinnervation.The hot spots were located in the middle of the PCA muscle, severalmillimeters from the median raphe, and covered 30-40% of the musclesurface area.

During chronic pacing, it would be desirable to stimulate above thefusion frequency for the PCA muscle so that a smooth abduction of thevocal cord would be achieved. In each animal, the chronically denervatedmuscle had a lower fusion frequency than its innervated partner. In achronic implant, it would be desirable to lower the rate of stimulationunder 30 Hz closer to that of the fusion frequency (mean: 21.77 Hz) toconserve charge. FIG. 3 shows views of a clinical patient with laryngealhemiplegia both at rest and during stimulation with 4.5 mA at 24 Hz. Asthe pulse duration was increased, the efficiency in activatingchronically denervated muscle increased and surpassed that of theinnervated muscle at durations greater than 1-2 ms. However above 2 ms,stimulation became less efficient for both muscles because of chargeloss through current shunts normally found in tissue. The amount ofvocal cord excursion was only 40-70% of that produced with stimulationof the normally innervated muscle, indicative of denervation atrophy andloss of muscle contractility.

Sanders I et al., Arytenoid Motion Evoked By Regional ElectricalStimulation Of The Canine Posterior Cricoarytenoid Muscle, Laryngoscope.April 1994; 104(4):456-62, incorporated herein by reference,systematically evaluated stimulation delivered to the denervated caninePCA muscles, using single-stranded, stainless steel electrodes 1 cm inlength. Measures of abduction were obtained following an overdose ofcurare designed to mimic vocal fold paralysis via neuromuscularblockade. After RLN section and 2 weeks' time, measures of abductionwere repeated in these animals. Results documented 3 mm of vocal cordexcursion with 1 ms, 30 Hz, and 1-50 mA.

Sanders I., Electrical Stimulation Of Laryngeal Muscle, Otolaryngol ClinNorth Am. October 1991; 24(5):1253-74, incorporated herein by reference,left 4 dogs undisturbed for 6 months to allow atrophy to occur. After 6months of atrophy, the responses of the animals had decreased to roughly60% of initial values. The two dogs that did not undergo stimulationcontinued to atrophy during the following 4 months to 40% of initialvalues. The two dogs that underwent electrically induced exercise,however, increased their responses dramatically. Not only had theirresponses returned to normal, but they were uniformly greater thannormal, the average approximately 200% that of their initial denervatedstate. Gross examination of the excised larynges demonstrated that thestimulated group had maintained muscle bulk while the non-stimulatedgroup was noticeably atrophic. Denervated dog PCA could be stimulatedwith pulses as short as 2 ms. Any lower, and the needed voltage jumpedexponentially. Sanders used similar pulse widths to chronicallystimulate denervated muscle for months. This is the minimum andpresupposes that the electrode is placed directly adjacent to themuscle.

Zealear D L et al., Reanimation Of The Paralyzed Human Larynx With AnImplantable Electrical Stimulation Device, Laryngoscope. July 2003;113(7):1149-56, incorporated herein by reference, reported on four humanpatients implanted with adapted pain pacemaker systems. In the fourpatients tested, electromyographic (EMG) motor unit activity was presentin the PCA and thyroarytenoid (TA) muscles during voluntary effort.These recordings showed inappropriate firing patterns. For example,inspiratory motor unit activity was recorded from the TA musclecharacteristic of a PCA motor unit. In particular, a deep inspiration orsniff increased the rate of firing of individual motor units andenhanced the overall interference response. This inappropriate activitywas indicative of synkinetic reinnervation.

In follow-up sessions, the optimum stimulus parameters for vocal foldabduction were studied. A one- to two-second train of one-millisecondpulses delivered at a frequency of 30 to 40 pulses per second (pps) andamplitude of 2 to 7 V effectively produced a dynamic airway. One to twoseconds of stimulated abduction allowed sufficient air exchange witheach breath. Although a previous study in the canine found 2-millisecondduration as the optimum pulse width for recruiting both reinnervated andnon-reinnervated muscle fibers, the maximum pulse width that thestimulator could deliver was 1 millisecond. A frequency of 30 to 40 ppsgenerated a fused, tetanising muscle contraction and a smooth vocal foldabduction with maximum opening. The device was set to deliver an averageof 10 stimulus sequences (bursts) every minute to match the patient'srespiratory rate at a moderate level of activity. The ideal stimulusamplitude was one that evoked maximum vocal fold opening withoutinducing discomfort or nociception. At this amplitude, the patient couldfeel the stimulus, which helped entrain inspiration to the stimuluscycle. Stimulated abduction significantly increased the magnitude ofglottal opening in patients 1 to 5 from preoperative levels (P<0.0008).Stimulated glottal opening was large in patients 1, 3, and 4 (3.5-7 mm)and moderate in patient 2 (3 mm). In patient 5, stimulation alsoproduced a large abduction of 4 mm, but the response was delayed intime.

In order to decrease current spread and the high power requirements ofFES devices, the placement of electrodes should localize current to thetarget muscle or nerve (if the muscle is innervated—even if it issynkinetically reinnervated) as much as possible. This may beaccomplished by placing the electrodes inside the muscle, or on itssurface, a procedure that produces two technical problems: (1) surgicalexposure of the muscle causes scarring which eventually decreases musclemobility; and (2) because electrodes must be close to their target to beefficient, they are exposed to muscle movement. The constant abrasion ofthe electrode against the muscle breaks the electrode or causesextensive fibrosis in the muscle. This difficulty plagued the earlydevelopment of the cardiac pacer and persists today in many experimentsinvolving chronic stimulation of denervated muscle, including thedenervated PCA. As a result, there has not been a truly successfulchronic device for stimulation of denervated muscle.

In 1992 for unilateral vocal cord paralysis, Goldfarb used the electricactivity of the healthy side as a trigger for synchronization withbreathing and vocalization. See, U.S. Pat. No. 5,111,814. This method isnot applicable for the clinically more relevant bilateral paralysis.Lindenthaler described a pacemaker for bilateral vocal cord palsy due toautoparalysis (equivalent to synkinetic Recurrent Laryngeal Nerve (RLN)reinnervation), which is triggered by another muscle or nerve signalthat is activated synchronic to breathing, e.g., diaphragm breathingmuscles, infrahyoidal muscles of the neck. The pacemaker then stimulatesstructurally intact but autoparalytic nerve. See, U.S. Pat. No.7,069,082.

For a real and complete rehabilitation of some patients with uni- orbilateral vocal cord paralysis or even in patients with a larynxtransplantation a mere restoration of a single movement function ofvocal cords by a pacemaker is not sufficient. In some cases evenessential, is a pacemaker that can stimulate opening of vocal cords(e.g., to achieve sufficient breath for physical activities) as well ascomplete closure and tension of vocal cords (e.g., for vocalization andin combination with larynx elevation during swallowing for protectionagainst aspiration). An optimal coordination of stimulated larynxmovements with breathing cycle, intentional vocalization and swallowingreflex is necessary for that.

A stimulation of opening and closing of vocal cords might be helpful topreserve the full dynamic range of vocal cord movability by preventing afixation of the cricoarytenoid joint. The necessary electrodes orsensing devices for detecting triggers and for stimulation ofautoparalytic nerves or direct stimulation of paralyzed muscles of thelarynx itself must not damage healthy tissue. In addition, theimplantation procedure should also not cause harm.

Current surgical techniques all involve the exposure of the endings ofthe RLN or the exposure of the opening muscle (i.e., PosteriorCricoarytenoid Muscle, (PCA)) of the larynx. To achieve this, othermuscles have to be cut (e.g., infrahyoidal muscles or pharyngealconstrictor muscle) and vessels and nerves in the vicinity may bedamaged causing an impaired mobility of the larynx during swallowing andimpaired sensitivity of mucus membranes with an increased risk offoreign body aspiration. Furthermore, scarring of all those tissues maydiminish stimulated movements in the long run.

In addition, free placement of electrodes through the tissue to thetarget muscle (or nerve) may cause a high mechanical stress in theelectrode leads which may cause lead wire breakage in delicateelectrodes. Thus, placing or laying of the electrode in such a way thatprotects the electrode more may be helpful.

In order to decrease current spread and the high power requirements ofFES devices, the placement of electrodes should localize current to thetarget muscle or nerve (if the muscle is innervated—even if it issynkinetically reinnervated) as much as possible. This may beaccomplished by placing the electrodes inside the muscle or at itssurface, a procedure that produces two technical problems: (1) surgicalexposure of the muscle causes scarring which eventually decreases themuscle's mobility; and (2) because electrodes must be close to theirtarget to be efficient, they are exposed to muscle movement. Theconstant abrasion of the electrode against muscle breaks the electrodeor causes extensive fibrosis in the muscle. This difficulty plagued theearly development of the cardiac pacer and persists today in manyexperiments involving chronic stimulation of denervated muscle,including the denervated PCA. As a result, there is not currently atruly successful chronic device for stimulation of denervated muscle.

An open surgery is much more invasive than a needle insertion. Insertionneedles or puncture needles are typically straight and not curved,consisting of one part. For some situations, however, it is not possibleto reach the target point (e.g., inside the subject's body or adifferent position outside the body then where the insertion started) ina straight line from the outside of the body or starting from cavitiesinside the body.

SUMMARY OF THE INVENTION

In accordance with one aspect of the invention there is provided amethod of introducing interface elements for interfacing with laryngealstructures of a subject such as for diagnosis or treatment of alaryngeal impairment. The method involves generating a tunnel ingeographical relation to the lateral wing of the cricoid cartilage ofthe subject and introducing at least one interface element via thetunnel for interfacing with at least one laryngeal structure of thesubject.

In various alternative embodiments, at least a portion of the tunnel maybe subperichondral on an inside of cricoid cartilage lamina. A portionof the tunnel may be on an outside of cricoid cartilage lamina. Aportion of the tunnel may be inside of a cricoid cartilage wall, forexample, formed in a curve in the inside of the cricoid cartilage wall.A portion of the tunnel may be partly inside of a cricoid cartilage walland partly subperichondral on an inside of cricoid cartilage lamina. Aportion of the tunnel may be partly inside of a cricoid cartilage walland partly on the outside of cricoid cartilage lamina.

In various alternative embodiments, an interface element may bepositioned, implanted temporarily, implanted permanently, brought inplace, inserted, and/or affixed. An interface element may include anelectrode, a sensor, a catheter, a delivery device, a heat deliverydevice, a cold delivery device, a surgical device, a needle, a probe, alight transmission device, a tissue, a bulking material, light, heat,cold, fluid, drug, medicine, nutrient, radiation, or material. Alaryngeal impairment may include unilateral vocal cord paralysis,bilateral vocal cord paralysis, dysphonia, dysphagia, and/or tendency ofaspiration. A single interface element may be positioned unilaterally,multiple interface elements may be positioned unilaterally, or multipleinterface elements may be positioned bilaterally. An interface elementmay be placed in communication with a controller that is implanted intothe subject. A plurality of interface elements may be placed incommunication with a controller that independently controls theinterface elements, or each of a plurality of interface elements may beplaced in communication with a separate controller such that eachinterface element is independently controlled by its respectivecontroller.

In various alternative embodiments, certain aspects of the method may beperformed in the surgical field of a neck incision and may be visuallymonitored intraoperatively, monitored intraoperatively by neuralmonitoring, monitored intraoperatively by monitoring ofelectromyographical signals, and/or performed endoscopically. Navigationof the interface element(s) and/or other implements may be performedusing palpation, x-ray, CT, MRI, electrical test stimulators, aschablone manufactured according to general or the specific computertomography data of the subject, a mask of the throat and mandible,and/or by use of a 2 or more dimensional video navigation system inrelation to at least one of computer tomography, X-ray, MRI, andultrasound data of the subject. Various elements may be repositioned,for example, with a different angle, a different direction, or adifferent starting point.

In various alternative embodiments, at least one laryngeal structure(e.g., a single vocal cord, both vocal cords, the epiglottis, or apharyngeal constrictor) may be interfaced using the interfaceelement(s), and the interface element(s) may be positioned forinterfacing with a muscle, nerve, or receptor. Such interfacing mayinclude, among other things stimulating a laryngeal structure,activating a laryngeal structure, blocking a laryngeal structure,inhibiting operation of a laryngeal structure, moving a laryngealstructure, removing a portion of a laryngeal structure, repairing alaryngeal structure, delivering a material to a laryngeal structure, ormonitoring a laryngeal structure. Moving a laryngeal structure mayinclude opening, closing, or varying tension of the laryngeal structure.The interfacing may include receiving and/or recording electromyographicsignals of a related muscle and/or may include receiving and/orrecording electroneurographic signals of a related nerve. In variousalternative embodiments, various types of stimuli (e.g., electricalenergy or drugs) may be delivered to a laryngeal structure via theinterface element(s).

In certain embodiments, the interface element may include an electrode,in which case a portion of the electrode may be routed percutaneouslythrough the skin to the outside of the subject and connected to anexternal stimulator for a certain duration to verify efficacy of theinterfacing with laryngeal structures. In other embodiments, theinterface element may include a sensor, in which case a portion of thesensor may be routed percutaneously through the skin to the outside ofthe subject and connected to an external recorder for a certain durationto verify efficacy of the interfacing with laryngeal structures. In yetother embodiments, the interface element may include a catheter, inwhich case a portion of the catheter may be routed percutaneouslythrough the skin to the outside of the subject and connected to anexternal pump for a certain duration to verify efficacy of theinterfacing with laryngeal structures. In some embodiments, the certainduration may be from 1 to 60 minutes. In other embodiments, the certainduration may be from 1 to 24 hours. In yet other embodiments, thecertain duration may be from 1 to 7 days. In still other embodiments,the certain duration may be from 1 to 20 weeks. An interface element(e.g., an electrode, sensor, or catheter) may be permanently connectedto a surgically implanted controller (e.g., a stimulator, recordingdevice, or pump) in the case efficacy is proven or may be removed fromthe subject in the case efficacy has not been proven.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing features of the invention will be more readily understoodby reference to the following detailed description, taken with referenceto the accompanying drawings, in which:

FIG. 1 shows a horizontal cut through the larynx and an insertion pathfor inserting an interface element into a space between PCA muscle andcricoid cartilage plate according to illustrative embodiments of thepresent invention;

FIG. 2 shows a lateral view of the larynx and an insertion path forinserting an interface element into the space between the PCA muscle andthe cricoid cartilage plate according to illustrative embodiments of thepresent invention;

FIG. 3 shows a horizontal cut through the larynx and an insertion pathfor inserting an interface element into a subperichondral tunnelaccording to illustrative embodiments of the present invention;

FIG. 4 shows a lateral view of the larynx and the insertion path for aninterface element inserted into the subperichondral tunnel according toillustrative embodiments of the present invention;

FIG. 5 shows a horizontal cut through the larynx and an insertion pathfor inserting an interface element into a drill hole through cricoidcartilage according to illustrative embodiments of the presentinvention;

FIG. 6 shows a lateral view of the larynx and the insertion path forinserting an interface element into a drill hole through the cricoidcartilage according to illustrative embodiments of the presentinvention;

FIG. 7 shows a horizontal cut through the larynx and an insertion pathfor inserting an interface element into a subperichondral tunnel on aninside of thyroid cartilage lamina according to illustrative embodimentsof the present invention;

FIG. 8 shows a lateral view of the larynx and an insertion path forinserting an interface element into the subperichondral tunnel on theinside of the thyroid cartilage lamina according to illustrativeembodiments of the present invention;

FIG. 9 shows a front view of the larynx and the tuberculum thyroideumcaudale as a landmark of the starting point of the insertion accordingto illustrative embodiments of the invention;

FIG. 10 shows a 3-dimensional computer tomography reconstruction of thevocal cord that includes the tuberculum thyroideum caudale according toillustrative embodiments of the invention;

FIG. 11 shows a lateral view of a 3-dimensional computer tomographyreconstruction of the vocal cord and the insertion path for inserting aninterface element into an insertion route through the cricoid cartilageaccording to illustrative embodiments of the present invention;

FIG. 12 shows a 3-dimensional computer tomography reconstruction of thevocal cord from below illustrating the cricoids cartilage arch thicknesstowards the cricoids cartilage plate according to illustrativeembodiments of the invention;

FIG. 13 shows a 3-dimensional computer tomography reconstruction of thevocal cord from behind illustrating the exit point of the insertionroute through the crycoid cartilage appearing under the posteriorcricoarytenoid muscle according to illustrative embodiments of theinvention;

FIG. 14 shows a 3-dimensional computer tomography model of the vocalcord photographed from below illustrating that the cricoid cartilagearch thickens towards the cricoid cartilage plate according toillustrative embodiments of the invention;

FIG. 15 shows a 3-dimensional computer tomography model of the vocalcord photographed from behind according to illustrative embodiments ofthe invention;

FIGS. 16A-M show an interface element insertion system having a curvedneedle system and an insertion path between muscle and cartilageaccording to illustrative embodiments of the present invention;

FIGS. 17A-H show a lateral view of the larynx and the insertion path ofan interface element between muscle and cartilage according toillustrative embodiments of the present invention; and

FIG. 18 shows a lateral view of the larynx and an insertion path forinserting an interface element between muscle and cartilage according toillustrative embodiments of the present invention.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Definitions. As used in this description and the accompanying claims,the following terms shall have the meanings indicated, unless thecontext otherwise requires:

A “subject” may be a human or animal.

An “interface element” is an element for directly or indirectlyinterfacing with the laryngeal structures of a subject and may include,but is in no way limited to, an electrode (e.g., for conveyingelectrical signals to and/or from an anatomical structure such as forstimulating, sensing, recording, etc.), a sensor (e.g., for monitoringan anatomical structure), a catheter (e.g., for conveying a fluid orother material to and/or from an anatomical structure), a deliverydevice (e.g., a pump or syringe for delivering a medication, drug,nutrient, fluid, or other material to an anatomical structure), a heatdelivery device (e.g., a cauterization tool), a cold delivery device(e.g., a cryogenic tool), a surgical device (e.g., a scalpel or biopsytool for removing tissue, a suturing device for repairing tissue, orother implement used in surgical procedures), a needle, a probe (e.g.,for physical manipulation or stimulation of an anatomical structure), alight transmission device (e.g., a laser, optical fiber, scope, camera,light), a tissue, a bulking material, or other thing that can bedelivered for interfacing with the laryngeal structures (e.g., light,heat, cold, fluid, drug, medicine, nutrient, radiation, or othermaterial), to name but a few. An interface element may be used inconjunction with an integral or separate controller, such as astimulation device (e.g., a pacer), a sensing device (e.g., a monitor),a recording device, and/or a manipulation device (e.g., a handle), toname but a few. In some cases, such a controller may be portable,wearable, and/or implantable. In some cases, such a controller may becapable of operating multiple interface elements either in unison orindependently, e.g., for performing different functions on differentlaryngeal structures or for redundancy in case of a failure of aninterface element or a component of the controller. In some cases, sucha controller may be directly connected to an interface element (e.g.,via a wire) or may interact with an interface element remotely (e.g.,via a wireless communication interface). Thus, in various embodiments,multiple interface elements may be used with separate controllers, ormultiple interface elements may be used with a single controller, andthe interface elements may interact with the controller(s) in the sameway or in different ways.

A “laryngeal structure” is a structure associated with the larynx,including, but not limited to, a single vocal cord, both vocal cords,the epiglottis, a pharyngeal constrictor, a supraglottic sphincter, orrelated structures (e.g., tissue, muscle, nerve, bone, cartilage), toname but a few.

In the context of the laryngeal structures of a subject, “unilaterally”means that an interface element is placed on one side of the body, vocalcord, or other structure (i.e., typically either the left side or theright side), and “bilaterally” means that an interface element is placedon each side of the body, vocal cord, or structure (i.e., typically boththe left side and the right side). A “wing” is a part or aspect of thelaryngeal structure.

A “needle” is an implement for forming a tunnel or for otherwisedirectly or indirectly positioning an interface element and may include,but is in no way limited to, a needle, a raspatorium, or a drill, toname but a few. In various embodiments, a needle may be solid or hollow,may be straight or bent in one or more places, and/or may be of fixedlength or variable length (e.g., by telescoping).

A “thread” is used for directly or indirectly positioning an interfaceelement and may include, but is in no way limited to, a thread, string,rope, chain, fiber, wire, filament, or tether, to name but a few.

“Repositioning” of a needle, interface element, or other thing and“re-generating” a tunnel may include changing the angle, direction,and/or starting point.

In certain contexts, terms such as “introducing,” “positioning,”“placing,” and “inserting” may be used to refer to the same or similaroperations, particularly with regard to forming a tunnel, inserting athread, and/or positioning an interface element.

Embodiments of the present invention include endoscopically controlled,minimally invasive positioning of an interface element. The placementsystem and method reduce the risks related to a surgical procedure andat the same time allows an adjustment of stimulation to a laryngealstructure of the subject in vocalization, breathing or swallowing byalternatively stimulating opening, closing or elevation of the larynx.In addition, embodiments may allow more than one interface element to beinserted (e.g., bilaterally, or separate elements for opening andclosing or larynx elevation). “Pull through” techniques may requirespecial reinforcements of the interface element to accommodate tractionstress. Pushing in the interface element under endoscopic view is anespecially gentle method. Subperichondral or intra-chondral routing ofthe interface element may give better mechanical protection andelectrical stimulation through the perichondrium, which may protectagainst corrosion of the interface element. Intra-operative endoscopiccontrol and stimulation ensure optimal positioning of the interfaceelement. Stimulation of opening and closing encourages a betterpreservation of movability of the crico-arytenoid joint and offers abetter dynamic range potentially resulting in better exercise abilitiesand better speech quality in subjects than subjects without thestimulation. Bilateral interface element placement also offers theadvantage of new three-dimensional electric dipole vectors for optimalstimulation, which may further improve the flexibility. Bilateral,separately controlled interface elements may also provide a highersafety in case of device failure. For example, if one side fails, theother side may (partially) compensate until the subject seeks clinicalhelp.

Various exemplary embodiments are described with reference to theinsertion of an electrode for facilitating the movement or stimulationof vocal cords. Other types of interface elements, however, may be used,in addition to, or lieu of, to facilitate interfacing with laryngealstructures generally according to various embodiments of the presentinvention.

In order to decrease current spread, the placement of electrodespreferably localizes current to a related anatomical structure (e.g.,target muscle or nerve) as much as possible by a minimally invasivesurgery. A needle insertion technique, instead of an open surgery, mayprovide the solution. In one embodiment, the capability of reaching alocation or target (e.g., inside a subject's body) is provided byinsertion of a curved needle system capable of going around corners,around obstacles and/or cartilage. In another embodiment, a straightpath or tunnel may be used to reach the target or location.

Embodiments of the present invention also permit a minimally invasive,two stage implantation procedure to be possible. First, the interfaceelement is inserted and a test stimulation session may be conducted overtime, e.g., over several days or weeks, to show efficiency of thesystem. Then, when efficiency is positively verified a stimulator mayalso be implanted or when efficiency is not positively verified theinterface element may be retracted out of the body without a complicatedsurgery.

Embodiments of the present invention are directed to the implantation ofan interface element in the larynx using minimally invasive techniques.One embodiment includes straight tubular interface elements (e.g.,electrodes) that may be used by inserting the elements in a “pull back”procedure after the interface element is attached to a thread that hasbeen previously inserted along an insertion path.

FIG. 1 shows a horizontal cut through the larynx in the plane of thearytenoid cartilages. The projected way of the thread for inserting theinterface element according to one specific embodiment is marked with abold black interrupted line, insertion path 106. The discussion belowexplains how the interface element may be brought in the space betweenthe PCA muscle 108 and the cricoid cartilage plate 110. In addition, thevicinity to the recurrent laryngeal nerve 107 and its medial branch isshown. FIG. 2 shows a lateral view of the larynx to illustrate how thethread for the pull back procedure may be directed ventrally below thelarynx.

Under direct endoscopic laryngoscopic view, a slightly curved needle maybe inserted into the backside of the larynx, called the postcricoidalregion. The needle is inserted above the posterior cricoarytaenoid (PCA)muscle 108, which originates from the cricoid cartilage plate 110 andinserts at the arytenoid cartilage 104. The cricoid cartilage 115includes a cricoid cartilage arch 103 and the cricoid cartilage plate110, with the bottom of the cricoid cartilage 115 being the part on theanterior side of the vocal cord, the top of the cricoid cartilage 115being the part on the posterior side of the vocal cord, and the twolateral parts or wings being on the left and on the right of the vocalcord. The PCA muscle 108 is the main and only opening muscle of thevocal cords 102. A branch of the recurrent laryngeal nerve 107 runsbeneath it on the surface of the cricoid cartilage plate 110 frominferior lateral to superior medial. This nerve branch supplies the PCAmuscle 108 with motor nerve fibers. The needle may be pushed laterallyand downwardly towards the cricothyroid joint 105 in the subperichondralspace on the posterior side of the cricoid cartilage plate 110. A tunnelmay be preformed, e.g., with a raspatorium, in order to make thisinsertion easier. The needle may then be pushed out of the larynx in amore forward direction into the neck soft tissue. Attention should bepaid to not penetrate the piriform sinus of the hypopharynx 109.Tracheal cartilage 201 is shown in FIG. 2 as a reference point.

The needle is thus held in the neck soft tissue. This is achievedthrough a small external surgical approach. The skin may be incised afew centimeters longitudinally or horizontally and laterally near thelower end of the larynx. The tissue between the larynx and the neckvessel sheath may be separated to create a space to find the needle andto protect the big neck vessels. In some cases, it may be helpful torotate the larynx a little to the opposite side. Once the needle hasbeen found, it is caught. A thread is fixed (e.g., knotted or by otherconnecting means) to the interface element tip and the needle. Theneedle is pulled back with the interface element connected to it by thethread. The interface element is then pulled in place. The interfaceelement should to be strong enough to withstand the traction forces. Theposition of the interface element may be corrected or optimized byvisually controlling the movement of the vocal cord 102 in response tostimulation, such as electrical stimulation. Once the best position hasbeen established the interface element may be fixed with a suture to theside of the cricoid cartilage 115 or by other means. After a finalcontrol of electrical response, the thread may be cut at the surface ofthe mucous membrane on the back side of the larynx. The little pieces ofthread that may be left at the electrode tip subsequently dissolve bythemselves. A pacer housing may then be implanted via a smallsubcutaneous tunnel into a subcutaneous pocket, e.g., on the chest wall.A second incision on the chest wall to affix the pacer housing may benecessary. The incisions are closed with sutures or clips as well knownto those skilled in the art. Enough time for wound healing is allowedbefore the device is used.

Alternatively, the needle may be pushed in a more downward direction sothat it enters the neck in the space between the trachea and theesophagus. The advantages of this method are: 1) less tissue damage tothe larynx and its connective tissue gliding space which is importantfor a good larynx elevation (during swallowing and speaking withdifferent tone pitches), 2) the electrode tip is laying close to thecartilage surface which protects it from mechanical forces, 3) theelectrode tip runs along the expected location of the nerve branchessupplying the posterior arytenoid muscle, and 4) more laterally, thenerve stem or other branches of the recurrent laryngeal nerve come closeto the multi-electrode so that the electrode may be used for opening andclosing the vocal cord.

One embodiment may be an interface element inserted into asubperichondral tunnel on the outside of the cricoid cartilage arch 103,through a tunnel through the cricoid cartilage arch 103 to the posteriorsubperichondral space of the cricoid cartilage plate 110, or with thehelp of a needle through the cricoid cartilage 115 to the posteriorsubperichondral space of the cricoid cartilage plate 110. FIG. 3 showsan interface element inserted into a subperichondral tunnel, insertionpath 301 and FIG. 11 (to be described in more detail below) shows aninterface element inserted through the cricoid cartilage 115. As shown,the tip of the electrode reaches behind the cricothyroid joint 105 wherethe recurrent laryngeal nerve 107 divides into its branches. FIG. 4shows a lateral view of the electrode inserted into the subperichondraltunnel.

Similarly, FIGS. 5 and 6 show an interface element inserted into atunnel through the cricoid cartilage 115. The tunnel may be straight orbent according to the technology used to generate the tunnel. It may bepossible to reach the recurrent laryngeal nerve 107 more medially andtherefore better stimulate the opening movement of the vocal cord 102.The skin may be incised a few centimeters longitudinally or horizontallyand laterally near the lower end of the larynx where the cricoidcartilage 115 is or the skin may not even be incised and the needle isdirectly pushed through the skin.

After dissection of subcutaneous tissue the prelaryngeal “strap muscles”have to be moved medially or laterally. The upper end of the thyroidgland often covers the cricoid cartilage arch 103. It is dissected fromthe cartilage to expose the cricoid cartilage arch 103. This is usuallyeasily achieved, but care should be taken not to damage any nervestructures. In some cases, a vessel may have to be tied. Once thecricoid cartilage arch 103 with anterior thyrocricoid muscle sitting onit is exposed, the larynx is slightly turned to the opposite site. Theperichondrium of the cricoid cartilage 115 is incised. A subperichondraltunnel may be formed with a small curved raspatorium. The tunnel may beprogressed towards the cricothyroid joint 105 and extended a littlefurther either above or below it. The cricothyroid joint 105 may beidentified by palpation or by other means.

The stimulating electrode may be inserted into this tunnel. This may beachieved with an electrode which is stiff enough by itself or which isotherwise stabilized. Small hooks and/or a miniature endoscope like insialography (endoscopic examination of saliva ducts) or a tube that maybe split and fits the electrode in its lumen may be used to aidinsertion. The correct positioning of the electrode may be controlled bylaryngoscopic control of vocal cord movements. Once the best positionhas been established the electrode may be fixed with a suture, siliconeanchors or another kind of fixation to the side of the cricoid cartilage115. Small tags on the electrode lead may be used to achieve a goodfixation.

A pacermaker may then be implanted via a small subcutaneous tunnel intoa subcutaneous pocket, e.g., on the chest wall. A second incision on thechest wall to affix the pacermaker may be necessary. The incisions areclosed with sutures or clips as well known to those skilled in the art.Enough time for wound healing is allowed before the device is used.

Alternatively, the interface element may be routed through a tunnel(e.g., in the form of a drill hole) through the arch of the cricoidcartilage 103 itself towards the backside of the cricoid cartilage plate110. This would allow a lightly more medial position of the electrodetip and make it easier to stimulate the nerve branches to the PCA muscle108. For example, an electrode may be inside a needle during aninsertion, fixed inside the needle and then pushed out or held in placewhile the needle is pulled back, or the tip may be bent around the edgesof the tip of the needle like a “hooked-wire” electrode and, thus, isself-fixing when pulling the needle back, or the electrode may not beinside the needle during insertion but pulled inside after the needlehas been placed and then pushed out or held in place while the needle ispulled back. The advantages of this embodiment are: 1) reduced tissuedamage to the larynx and its connective tissue gliding space which isimportant for a good larynx elevation (during swallowing and speakingwith different tone pitches) and 2) the electrode tip is laying close tothe cartilage surface or inside the cartilage which protects it frommechanical forces.

The navigation for the insertion path or route may be done by the helpof landmarks only, or by the assistance of a template manufacturedaccording to general or the specific computer tomography data of thesubject, or by the assistance of a mask of throat and mandiblecomparable to radiation masks, or with a three or more dimensional videonavigation system in relation to the computer tomography, X-ray, MRI orultrasound data of the subject. When the needle is pushed through thecartilage and exits on the backside of the cartilage or the electrode isinside the needle with the tip of the electrode extending slightlybeyond the needle tip, the needle may then be connected to an electricalstimulation apparatus to verify the position of the needle tip by theeffectiveness of the vocal cord opening evoked by the electricalstimulation. The needle may be insulated in selected areas (e.g.,insulated except for the tip) or may not be insulated at all. If theeffectiveness of the vocal cord opening is not satisfactory, the needlemay be pulled back and pushed through the cartilage again at anotherangle till the needle leaves the cartilage on the other side and ispushed out in a certain position between posterior cricoarytenoid muscleand cricoid cartilage. The process of verifying the position of theneedle tip may then be repeated. For example, the needle or theelectrode inside the needle with the tip of the electrode extendingslightly beyond the needle tip may then be connected to an electricalstimulation apparatus to verify the position of the needle tip by theeffectiveness of the vocal cord opening evoked by the electricalstimulation and so on.

One embodiment may use straight tubular electrodes inserted into atunnel on the inside of the thyroid cartilage. FIG. 7 shows an electrodeinsertion into a subperichondral tunnel on the inside of the thyroidcartilage lamina, insertion path 701. FIG. 8 shows the lateral view. Asshown in FIGS. 7 and 8, the tunnel declines a little to reach thedividing region of the recurrent laryngeal nerve 107. It may not benecessary in all cases to have the electrode reach as far as thedividing point of the recurrent laryngeal nerve 107.

A small, preferably horizontal, prelaryngeal skin incision in the neckmay be made. The thyroid cartilage 101 may be exposed in the anteriorpart. A tunnel may be made (e.g., by drilling a hole) preferably halfway between the superior and inferior thyroid incisures (which is aboutthe height of the glottic plane) in the anterior third of the cartilage.The tunnel may be large enough to enter with a small raspatorium, acurved needle (e.g., a curved needle system or a telescopic curvedneedle system), or some other tool to create a subperichondral tunnel atthe inside of the thyroid cartilage 101. The tunnel may be made slightlydownwards in the direction of the cricothyroid joint 105. It extendseither above or below the joint into the region of the recurrentlaryngeal nerve 107 and its dividing point. Finding the way towards therecurrent laryngeal nerve 107 near the cricothyroid joint 105 may benavigated by palpation, x-ray, CT/MRI-navigation or the use ofelectrical test stimulators. In some cases, the tunnel may not progressas far as the joint region if only the anterior branch is stimulated(for adduction of the vocal cord).

Into this tunnel, the stimulating electrode may be inserted. This may beachieved with an electrode which is stiff enough by itself or has beenotherwise stabilized. Small hooks and/or a miniature endoscope like insialography (endoscopic examination of saliva ducts) or a tube that maybe split and fits the electrode in its lumen may be used to aidinsertion. The correct positioning of the electrode may be controlled byvisual control of larynx movements. Once the desired position has beenestablished the electrode may be fixed near the tunnel with a suture orby other means. A pacermaker may then be implanted via a smallsubcutaneous tunnel into a subcutaneous pocket, e.g., on the chest wall.A second incision on the chest wall to affix the pacermaker may benecessary. The incisions may be closed with sutures or clips as wellknown to those skilled in the art. Enough time for wound healing isallowed before the device is used. Alternatively, or in addition, theinsertion path or a second insertion path may be advanced morecranially. An electrode may be placed there to stimulate thesupraglottic sphincters (muscles closing the larynx entrance, protectionagainst food/foreign body aspiration). Different electrodes may beinserted for the vocal cord(s) and for the supraglottic sphincters.

The advantages of this embodiment are: 1) reduced tissue damage to thelarynx and its connective tissue gliding space which is important for agood larynx elevation (during swallowing and speaking with differenttone pitches). 2) the electrode tip is laying close to the cartilagesurface beneath the perichondrium which may protect it from mechanicalforces. The perichondrium is conductive for electrical currents andprobably prevents a sheathing of the electrode with excessive connectivetissue which “insulates” the electrode (e.g., increasing the electricalresistance and therefore the energy drain from the stimulation device tomaintain a constant stimulus effect). Also, corrosion of the electrodemay be reduced. 3) multiple electrodes may reach the nerve branches tothe internal thyroarytenoid muscle or the muscle itself and at its tipthe branching point of the recurrent laryngeal nerve. The electrode may,therefore, stimulate closing of the glottic gap, and enhancing thetension of the vocal cord as well as opening the glottic gap bystimulating the nerve branches to the posterior cricoarytenoid muscle.

Another embodiment may use a straight insertion path or tunnel forinserting an interface element into an insertion route through thecricoid cartilage. As shown in FIG. 9, the starting point of theinsertion path 903 may be near the tuberculum thyroideum caudale 901,which may be used as a landmark. The insertion point may start about afew millimeters in front or about up to 2 cm backward. Due to thevarying thickness of the cricoid cartilage 115, the height may not bevaried substantially in various embodiments.

FIG. 10 shows a front perspective view and FIG. 11 shows a lateral viewof a 3-dimensional computer tomography reconstruction of the vocal cordthat includes the tuberculum thyroideum caudale 901, which is marked byan arrow. FIG. 12 shows a 3-dimensional computer tomographyreconstruction of the vocal cord from below illustrating the cricoidcartilage arch 103 thickness towards the cricoid cartilage plate 110.Because the lateral walls of cricoid cartilage 115 are thickened at aparticular height, it is possible to reach almost midline even with astraight insertion route by beginning the insertion near or at thetuberculum thyroideum caudale 901. One insertion path may include astraight tunnel 1201 and another insertion path may include a saggitaltunnel 1103 (also marked with an asterick), which ends about below therecurrent laryngeal nerve (RLN). Thus, a needle may be inserted in astraight line through one or both of the lateral walls of the cricoidcartilage 115 in a direction to reach the nerve branches of therecurrent laryngeal nerve 107 which innervate the PCA muscle 108. Atother heights of the cricoid cartilage 115 (with less thickness), anangled or curved insertion route may be used along the inner and outerborders of the lateral walls of the cricoid cartilage 115 to stay insidethe walls. Therefore, the route of the needle may start to enter thecricoid cartilage 115 right after passing through the skin and may stayinside the lateral wall till the needle leaves the backside of thecricoid cartilage 115 directly near a branch of the recurrent laryngealnerve 107 innervating the PCA muscle 108.

FIG. 13 shows a 3-dimensional computer tomography reconstruction of thevocal cord from behind illustrating the exit point 1301 and 1303 of theinsertion route through the crycoid cartilage 103, 110 appearing underthe PCA muscle 108. Exit point 1301 shows where the straight tunnel 1201(shown in FIG. 12) exits and exit point 1303 shows where the saggitaltunnel 1203 (shown in FIG. 12) exits. FIG. 14 shows a 3-dimensionalcomputer tomography model of the vocal cord photographed from belowillustrating that the cricoid cartilage arch thickens towards thecricoid cartilage plate. Due to the thickness, it is possible to reachalmost midline 1401 with a straight tunnel 1403 or a saggital tunnel1405 ending about below the recurrent laryngeal nerve (RLN). FIG. 15shows a 3-dimensional computer tomography model of the vocal cordphotographed from behind. As shown, the midline 1501, the medialdirection 1503 of a tunnel, and the lateral direction 1505 of a tunnelare marked with white dotted lines.

FIG. 18 shows a lateral view of the larynx and an insertion path ortunnel for inserting an interface element 1803 between muscle andcartilage. The interface element 1803 may be connected to a pacemaker orstimulator 1806, which may be implanted via a small subcutaneous tunnelinto a subcutaneous pocket on the subject.

Embodiments of the present invention may also include an insertionsystem comprising a telescopic curved needle system for inserting aninterface element in a subject. The telescopic curved needle systemincludes one or more inner hollow needles having successively smallerdiameters than the outer portion of the telescopic curved needle systemand located inside of the outer portion. FIGS. 16A-16M show thetelescopic curved needle system at various stages during an insertionprocedure. At the beginning of the procedure, the telescopic curvedneedle system may initially be relatively straight when in itsunexpanded form as shown in FIG. 16A. The telescopic curved needlesystem may be inserted from outside of the body through a small incisionin the skin or by starting from cavities inside the body like thepharynx, the stomach, the colon and the like. The relatively straighttelescopic curved needle system may then be pushed forward in apre-planed angle or under the control of a navigation tool (e.g., bypalpation, x-ray, CT, MRI-navigation or the use of electrical teststimulators) with a certain force or speed until a certain length of thetelescopic curved needle system is inserted, or a landmark, e.g., abone, a cartilage and the like, is reached, or a target shown by thenavigation tool is reached. For example, under direct or endoscopiclaryngoscopic view, the relatively straight, unexpanded telescopiccurved needle system may be inserted into the backside of the larynx sothat it is pushed in-between the PCA muscle and the cricoid cartilage.

The first inner hollow needle 1603, which is totally hidden inside theouter portion of the telescopic curved needle system and has a smallerdiameter than the outer portion, may then be pushed out of the tip ofthe outer hollow needle 1604, which may stay in place. The first innerhollow needle 1603 may be pushed with a certain force or speed until acertain length of the telescopic curved needle system is inserted, or alandmark, e.g., a bone, a cartilage and the like, is reached, or atarget shown by the navigation tool is reached. For example, afterinserting the relatively straight, unexpanded telescopic curved needlesystem deep enough to be outside the space in-between the muscle 1602and the cartilage 1601 (on the other side of the muscle than theinsertion point was) and to reach the lower posterior lateral edge ofthe cricoid cartilage near the crico-thyroid joint, the first innerhollow needle 1603 may be pushed out of the tip of the outer portion ofthe telescopic curved needle system with a certain force or speed untilthe first inner hollow needle 1603 reaches a desired position, e.g.,leaves the body through the skin without hurting any important structureon its way through the tissue.

The telescopic curved needle system may not need to be further extendedif a desired length or target is reached. However, if one extension oredge of the telescopic curved needle system is not enough to reach thetarget, then a second inner hollow needle 1605, which is inside thefirst inner hollow needle and has a smaller diameter than the firstinner hollow needle, may be pushed out of the tip of the first innerhollow needle 1603, which may stay in place. The second inner hollowneedle 1605 may be pushed with a certain force or speed until a certainlength of the telescopic curved needle system is inserted, or alandmark, e.g., a bone, a cartilage and the like, is reached, or atarget shown by the navigation tool is reached.

For example, if a second extension or edge is preferred after the edgenear the cricoid joint then a second inner hollow needle 1605 may beused and pushed out of the tip of the first inner hollow needle 1603with a certain force or speed until the second inner hollow needle 1605reaches a desired position, e.g., leaves the body through the skinwithout hurting any important structure on its way through the tissue.The telescopic curved needle system may include additional inner needlesif necessary.

After the inner hollow needle 1603 or 1605 leaves the body through theskin, an electrical stimulation electrode 1606, e.g., with contacts in arow along the tip of the electrode 1606, may be inserted inside thewhole electrode insertion system of hollow needles. The electrode 1606may be inserted until the electrode's tip is positioned in a desiredlocation, e.g., in-between the PCA muscle 1602 and the cricoid cartilage1601, or even further to the insertion point of the curved needle system(it may even look outside the skin in the larynx). The curved needlesystem may then be retracted back into the laryngeal side of originalneedle insertion while keeping the electrode 1606 in position, e.g., byfixing it at the insertion point of the electrode 1606, for example,manually. Alternatively, the curved needle system may be retracted whileplacing the electrode 1606 in a desired position. When the curved needlesystem is totally extracted and the electrode 1606 is in its desiredpositioned, e.g., on its way in-between the posterior cricoid muscle1602 and the cricoid cartilage 1601, electrical energy may betransmitted through the electrode 1606. The electrical energy may betransmitted sequentially over one after the other electrical contactpads near the tip of the electrode 1606. The position of the electrode1606 may then be corrected or optimized by visually controlling themovement of the vocal cord in response to electrical stimulation andretracting the electrode 1606, if necessary. Alternatively, electricalenergy may be transmitted through the electrode 1606 before the curvedneedle system is totally extracted, thus allowing optimization of theelectrode 1606 position both by retracting and/or inserting theelectrode 1606.

A stimulation device 1806, such as a pacemaker (see FIG. 18) may then beimplanted via a small subcutaneous tunnel into a subcutaneous pocket.The insertion system including a telescopic curved needle system may beused in a variety of ways and applications, e.g., inserting an interfaceelement as shown in FIGS. 1-8.

Embodiments of the present invention may include an insertion systemcomprising a straight needle system or a curved needle system forinserting an interface element in a subject. FIGS. 17A-H show a curvedneedle system at various stages during an insertion procedure. As shown,the procedure begins by inserting the curved needle system 1703 fromoutside of the body through a small incision in the skin or by startingfrom cavities inside the body like the pharynx, the stomach, the colonand the like. The curved needle system 1703 may then be pushed forwardin a pre-planned angle or under the control of a navigation tool or viathe help of landmarks (e.g., a bone, a cartilage and the like) with acertain force or speed until a certain length of the curved needlesystem is inserted, the landmark is reached, or a target shown by thenavigation tool is reached. The navigation tool may include palpation,x-ray, CT or MRI navigation or the use of electrical test stimulatorsconnected to the interface element 1704. For example, the stimulator mayemit electrical energy via one or more contacts positioned at the tip ofthe interface element 1704, at selected areas along the interfaceelement 1704 (e.g., at non-insulated areas when the element includesinsulated and non-insulated areas) or along the whole interface element1704 (e.g., when the element is not insulated).

Under direct or endoscopic laryngoscopic view, the curved needle systemmay be inserted into the backside of the larynx so that it is pushedin-between the PCA muscle 1702 and the cricoid cartilage 1701. Afterinserting the curved needle system 1703 deep enough to be outside thespace in-between the muscle 1702 and the cartilage 1701 (on the otherside of the muscle than the insertion point was) and to reach the lowerposterior lateral edge of the cricoid cartilage near the crico-thyroidjoint, the curved needle system 1703 may turn around this edge of thecartilage 1701 because of its pre-curved shape. The curved needle system1703 may be pushed further until it reaches a desired position, e.g.,leaves the body through the skin without hurting any important structureon its way through the tissue.

After the curved needle system 1703 leaves the body through the skin, aninterface element 1704 such as an electrical stimulation electrode(e.g., with contacts in a row along the tip of the electrode) or acatheter, may be inserted inside the curved needle system. In anotherembodiment, an interface element 1704 is fixed to the tip of the curvedneedle system 1703 by a thread and the interface element 1704 isinserted from the outside by pulling the curved needle system 1703 backand thereby pulling the interface element 1704 back through the tissuevia the connected thread. The interface element 1704 may be inserteduntil the element's tip is positioned in a desired location, e.g.,in-between the PCA muscle 1702 and the cricoid cartilage 1701, or evenfurther to the insertion point of the curved needle system 1703 (it mayeven look outside the skin in the larynx). The curved needle system 1703may then be retracted back into the laryngeal side of original needleinsertion while keeping the interface element 1704 in position, e.g., byfixing it at the insertion point of the interface element 1704, forexample, manually. Alternatively, the curved needle system 1703 may beretracted while placing the interface element 1704 in a desiredposition. When the curved needle system 1703 is totally extracted andthe interface element 1704 is in its desired positioned, e.g., on itsway in-between the PCA muscle 1702 and the cricoid cartilage 1701, anitem may be transmitted through the interface element 1704, such aselectrical energy through an electrode or a drug through a catheter.Electrical energy may be transmitted sequentially over one after theother electrical contact pads near the tip of the electrode. Theposition of the interface element 1704 may then be corrected oroptimized by visually controlling the movement of the vocal cord inresponse to the transmitted item (e.g., electrical stimulation)interacting with the vocal cord, and retracting the interface element1704, if necessary. Alternatively, the item may be transmitted throughthe interface element 1704 before the curved needle system 1703 iscompletely extracted, thus allowing optimization of the interfaceelement 1704 position both by retracting and/or inserting the interfaceelement 1704, if necessary.

The pacer 1806 may then be implanted via a small subcutaneous tunnelinto a subcutaneous pocket. Embodiments of the present invention alsopermit a minimally invasive, two stage implantation procedure to bepossible. First, an interface element 1704, e.g., an electrode, may beinserted as disclosed above, but the stimulator itself is not implantedduring the same surgery but left outside the body. A test stimulationsession may then be performed over time, e.g., several days or evenweeks. If this test stimulation period shows efficiency, the pacer maybe sterilized, the electrodes may be connected to the pacer 1806 via asmall subcutaneous tunnel, and the pacer may then be implanted into thesubcutaneous pocket. If the test stimulation period shows not enoughefficiency, then the electrode may be retracted out of the body withouta complicated surgery by simply pulling the electrode back till its tipleaves the skin. The insertion system including a curved needle system1703 may be used in a variety of ways, e.g., inserting an interfaceelement 1704 as shown in FIGS. 1-8 and FIG. 18.

Although various exemplary embodiments of the invention have beendisclosed, it should be apparent to those skilled in the art thatvarious changes and modifications may be made which will achieve some ofthe advantages of the invention without departing from the true scope ofthe invention.

What is claimed is:
 1. A method of positioning a laryngeal interfaceelement for interfacing with a laryngeal structure of a subject, themethod comprising: tunneling through cricoid cartilage of the subject togenerate an interface insertion path with respect to vocal cordcartilage of the subject; positioning the interface element relative tothe laryngeal structure of the subject based on the insertion path.
 2. Amethod according to claim 1, further comprising: interfacing theinterface element with the laryngeal structure.
 3. A method according toclaim 2, wherein interfacing the interface element includes delivering adrug to the laryngeal structure via the interface element.
 4. A methodaccording to claim 2, further comprising: routing a portion of theinterface element percutaneously through the skin of the subject to theoutside of the subject, and connecting the interface element to anexternal verification device to verify efficacy of the interfacing withlaryngeal structures.
 5. A method according to claim 1, furthercomprising: coupling the interface element to an implantable interfacecontroller in communication with the interface element.
 6. A methodaccording to claim 1, wherein tunneling includes tunneling through thecricoid cartilage toward the cricothyroid joint.
 7. A method accordingto claim 1, wherein the insertion path ends between the cricoidcartilage and posterior cricoarytenoid muscle.
 8. A method according toclaim 1, wherein a portion of the insertion path may be inside of acricoid cartilage wall substantially parallel to the wall.
 9. A methodaccording to claim 1, wherein the laryngeal structure includes a vocalcord, both vocal cords, an epiglottis, a pharyngeal constrictor, asupraglottic sphincter, or a combination thereof.
 10. A method accordingto claim 1, wherein the laryngeal structure includes a muscle, a nerve,or both.
 11. A method according to claim 1, wherein the interfaceelement includes an electrode, a sensor, a catheter, or a combinationthereof.